John Lipsky, the No. 2 official at the International Monetary Fund, said global economic growth in the second half of this year will fall short of the fund’s forecast.

“Growth has slowed in this year’s second half,” he said in the text of a speech posted on the IMF’s website today, and added that “this sluggishness will persist into early 2011.” The Washington-based fund had forecast growth at a 3.75 percent annual rate for the second half.